Pallet transfer device



March 1, 1966 F. A. SOLSKI ETAL PALLET TRANSFER DEVICE 6 Sheets-Sheet 1Filed June 17, 1963 a W ld H l. Q W W K fl mm M M M f z f a i 5 j r MMarch 1, 1966 Filed June 17, 1963 F. A. SOLSKI ETAL PALLET TRANSFERDEVICE 6 Sheets-Sheet 2 awn 5945f March 1, 1966 Filed June 17, 1963 F.A. SQLSKI ETAL PALLET TRANSFER DEVICE 6 Sheets-Sheet 4.

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March 1, 1966 F. A. SOLSKI ETAL 3,237,759

' PALLET TRANSFER DEVICE Filed June 17, 1963 6 Sheets-Sheet 6 UnitedStates Patent 3,237,759 PALLET TRANSFER DEVICE Frank A. Solski,Bloomfield Hills, Mich., and Lyman K. Shepard, Upper Saddle River, N.J.,assignors to Standard Tool & ltlannfacturing Co. Filed June 17, 1963,Ser. No. 288,389

7 Claims. (Cl. 198-211) This invention relates to pallet transferdevices and particularly to a lowering and raising device whichtransfers pallets from one to another conveyor at opposite ends of amachine.

In a copending application of Solski et al., Serial No. 266,264, filedMarch 19, 1963, for Automatic Machining Device, a machine is illustratedand described having a bed on which transverse bolsters are mounted forsupporting ways on which pallets are advanced in steps from one to theother end of the machine. The pallets are advanced by a bar having pinsthereon which extend vertically between the pallets in one rotativeposition of the bar. The pallets are advanced to the next adjacent workperforming station when the bar advanced after which the bar is rotatedin a reverse direction to have the pins disposed horizontally to permitthe bar to be returned without interfering with the advanced pallets.After each advancement to a station, the pallets are oriented andclamped in precise position relative to the tool which operates on theworkpiece located in the fixture carried by the pallets. At certain ofthe stations, the pallet is rotated 90 in either direction while beingadvanced to the next station.

At each end of the machine, elevating and lowering mechanisms areprovided which are capable of transferring the pallets between the endstations and a return conveyor in the base of the machine. Each time thepallets are advanced, the endmost pallet is moved into the loweringmechanism which employs a lead screw for lowering the pallet onto thereturn conveyor. When the pallet reaches the forward end of the machine,it moves onto a carrier on a lead screw which raises the pallet to asupporting fixture from which it is advanced by the bar onto the ways ofthe machine.

The present invention has raising and lowering mechanisms and aconveying system which are improvements over those of theabove-mentioned application for letters patent. The return conveyor islocated along one side of the base to lower the height of the machineand to have a greater coolant capacity in the tanks within the base. Theraising and lowering mechanism employs a rotary motion for transferringthe pallets between the two conveyors. Such structure is not to bethought of as superseding the mechanism of the above set forthapplication but rather as a supplement thereto which can be employedadvantageously for certain applications.

The transfer mechanisms located at each end of the machine are ofexactly the same construction except being of the opposite hand as themechanisms face each other. The conveying mechanisms embody a hub havinga plurality of arms thereon herein illustrated as having three armsdisposed 120 apart on each of which a forked carrier is swingablymounted and connected to a control arm fixed to the spindle thereof. Asimilar control arm is secured to the fixed spindle on which the hubrotates near the end of which the center of a Y-shaped leveling elementis pivoted. The leveling element has three arms disposed 120 apart withthe ends pivoted on the control arms of the forked carriers at adistance from the centers of the spindle which is the same as that ofthe center of the leveling arm from the center of the hub spindle. Withthis arrangement the control arms on the forked carriers are maintainedat approximately from the vertical at all times throughout the 360rotation of the hub thereby maintaining the forks of the carriershorizontal in all positions.

The pallets are constructed to have a recess along the edges forreceiving the fingers of the fork so that the pallets at the ends of themachine can be advanced by the advancing bar into and from the forks ofthe carriers aligned with the ways of the machine. Upon the advancementof the hubs of the devices, the following carriers will be moved intoposition to deliver and receive a pallet upon the advancement of all ofthe pallets on the ways to the next succeeding machining stations. Theremoved pallet will be deposited upon the return conveyor and controlmechanism permits only the foremost pallet to be moved into the fork ofthe carrier disposed in alignment therewith and moved therefrom 120 to aposition from which it is advanced onto the ways at the front end of themachine. A new cycle of operation will be performed on the workpieceplaced in the fixture of the returned pallet.

The hub is driven by a fluid motor through a decelera tion valve whichis operated by one of three cam surfaces on the hub for reducing theflow of fluid to the motor so as to slow up the 120 advancement of thehub near the end of the 120 movement thereof and stop the advancement atwhich time a locating pin will enter one of three apertures in the hubto accurately locate the arms thereon at the end of each 120advancement. The sequence of operation of the transverse devices is tiedin with the movement of the pallets on the ways of the machine withinterlock controls for preventing the operation of the devices andmechanisms in case the pallets are not in exact position relative to thefork of the carriers. There is very little wear upon the carrier partsas each mechanism is operated three times to complete a 360 advancement.

Accordingly, the main objects of the invention are: to provide 120spaced arms on a driven hub on which pivoted forked carriers areretained in horizontal position at all times by a Y-shaped element whichmaintains crank arms on the carriers in parallel relation with eachother and with a fixed arm on the stationary hub spindle; to employ theadvancing bar of the machine for moving pallets to and from the fingersof the forked carriers of the transfer devices from and to the ways ofthe machine, to synchronize the movement of the transfer devices withthe movement of the pallets in the machine so that the devices areadvanced only after the pallets have been moved to the next station ofthe machine, and in general, to provide a pallet transfer device at eachend of a machine which is simple in construction, positive in operationand economical of manufacture.

Other objects and features of novelty of the invention will bespecifically pointed out or will become apparent when referring, for abetter understanding of the inven tion, to the following descriptiontaken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a broken perspective view of. a machine having transferdevices at the opposite ends thereof embodying features of the presentinvention;

FIG. 2 is an enlarged perspective view of one of the pallets employed inthe machine illustrated in FIG. 1 as viewed from the point 2 thereof;

FIG. 3 is an enlarged broken sectional view of the structure illustratedin FIG. 4, as viewed from the point 3 thereof;

FIG. 4 is an enlarged sectional view of the structure illustrated inFIG. 3, taken on the line 44 thereof;

FIG. 5 is an enlarged broken sectional view of the structure illustratedin FIG. 4 taken on the line 5-5 thereof:

FIG. 6 is an end view of the structure of FIG. 5 as viewed from thepoint 6 thereof;

FIG. 7 is a broken plan view of the structure illustrated in FIG. 4;

at which work is to be formed. A base 11 supports longitudinal stringers12 across which bolsters 13 are mounted for supporting tools whichoperation on the workpiece carried by pallets 14 in a fixture 15 mountedthereon. The fixtures may take any form depending upon the type ofworkpiece to be machined and the type of machine operations which are tobe performed thereon by the tools of the machine.

The pallet, as illustrated in FIG. 2, is square so that it can be turnedthrough 90 and advanced on the ways of the machine and a square spacer16 is mounted between the pallet 14 and the fixture 15. The spacer is ofreduced dimension to provide recesses 17 along the edges of the palletwhich slide along fingers 18 of the fork carrier 19 when moved from oronto the ways 21 of the machine. As illustrated in FIG. 5, each of thefingers '18 has a recessed detent 22 rockable on a pin 23 against aspring pressed plunger 24. The corners of the spacer 16 are of arcuateform 25, the outermost corners being engaged by the extensions 26 on thedetents to retain the pallet on the fingers 18. The cam relationshipbetween the corners 25 of the spacer and the extension 26 of the detent,permits the pallet to be advanced from the fingers or advanced thereintoby sliding over the extension 26 which is deflected by the cam surface27 on the forward end thereof. the fixture and workpiece thereon areadvanced into and from the fingers of the fork carriers at the ends ofthe ways of the machine and at the return end of the return conveyor.

At the finishing end of the machine, the pallet removed from the ways isdelivered onto the return conveyor which is continuously operating andwhich advances the pallet from the carrier fingers. The advancingmechanism for the machine 12 embodies sections of joined rods 30 havingpins 31 extending therefrom in pairs to project upwardly at the frontand rear edge of the pallet when the rod 30 is rotated to have the pinsdisposed vertically. The pallets 14 are accurately located in the ways21 by rail members 32 which have extending flanges 33 projecting intothe recesses 17 at the sides of the pallet. This accurately aligns therecesses of the pallet with a flange 34 on the fingers 18 to permit therecesses 17 to pass over the flanges 34 upon the next advancement of therods 30 toward the finish end of the machine. limit the advancement ofthe pallet on the fingers 18. The stop faces 35 are located at the endof blocks 93 which are accurately positioned by a dowel 94 and securedby screws 95 to the bottom of the yoke 84 in alignment with the recess96 along the bottom inner face of the fingers 18 of the fork carriers.The pallet slides along the recesses 96 and abuts the face 35 of theblocks 93 to locate the spacer -16 of the pallet assembly so that theextending end 26 of the detents engage the curved surfaces 25 at theextending corners of the spacer.

The operation of the transfer device 36 at the starting end of themachine and transfer device 37 at the finishing end of the machine isthe same and these devices are structurally identical.

A bracket 41 supports a housing 42 in which the teeth of a gear 43meshes with the teeth of a gear 44 keyed to a shaft in bearings 45. Theshaft 40 also carries a pinion gear 46 which has teeth in mesh with aring gear 47 having its teeth on the exterior surface thereof. The ringgear is located by dowels 49 on a rotatable hub In this manner, thepallets with Stop faces 35, as illustrated in FIGS. 6 and 7 48 to whichit is secured by screws 50. The cylindrical flange 51 of the housing 49is closely contacted by the hub 48 and the encompassing flange 50thereof to form a chamber 52 which contains a grease for the gears. Thehub 48 has three equally spaced arms 53 extending therefrom 120 apart, arib 54 strengthens the connections of the arms with the hub. The hub hasa central sleeve 55 containing bearings 56 mounted for rotation on astub shaft 57 which is located by dowels 58 and secured by screws 59 tothe housing 42. The sleeve 55 rotates between a pair of end washers 62and 63, all of which are retained in position on the stub shaft 57 by arectangular plate 64, which is secured by a tongue and groove connection65 to the stub shaft 57 fixed thereto by a screw 66. The plate 64 issecured at approximately 45 to the vertical on the end of the stubshaft. A Y-shaped leveling element 67 has three arms 68 extending from acentral aperture 69 containing a sleeve bearing 71 which pivots on astub shaft 72 secured to the rectangular plates 64 by a screw 73extending from the stub shaft. Each of the arms 68 is attached to a stubshaft 72 extending through the sleeve bearing assembly 71 in theaperture 69 at the ends of the arms for pivotally connecting the arms torectangular plates 74. The plates 74 are similar to the plate 64 and arefixed to stub shafts 75 on the ends of the arm 53 by a screw 66 and atongue and groove connection 76. The rectangular plates 64 and 74function as crank arms and are retained parallel at an angle ofapproximately 45 to the vertical, at all times. The stub shafts 75operate in sleeve bearings 77 between end Washers 78 at the end of eachof the arms 53.

The stub shaft 75 has a flange 81 thereon from which a cylindrical boss-82 extends. An aperture 83 in a triangular-shape yoke 84 extends overthe boss 82 and is positioned by a dowel 85 and secured by screws 86extending into the flange 81. The yoke has the pair of fingers 18extending therefrom to form a fork for the reception of a pallet havinga work supporting fixture thereon. The Y-shaped element 68 maintains thecrank arms 74 parallel to the crank arm 64 at all times. By maintainingthe crank arms 74 in the same position at all times, the fingers 18 ofeach fork carrier will remain in a horizontal plane in all positions ofrotation of the hub 48.

As illustrated in FIG. 7, the pallet 14 disposed within the fork carrier19 is aligned with the ways 21 of the machine. The pallet is in positionto be engaged by the endmcst pin 31 when the rod 30 has advanced to theleft and has been rotated 90. The pin slides the pallet from the fingers'18 onto the ways 21 when the rod 30 is moved to the right, whichmovement advances all of the pallets 14 along the ways 21 to the nextsucceeding station at which a work operation is to be performed. Thefork carrier 19 of the transfer device 36 is located at station A whilethe next suceeding fork carrier 19 is located at station B. The forkcarrier located at station B is aligned with the endmost pallet 14 on areturn conveyor 97 which advances the pallets from the finishing end ofthe machine to the starting end thereof. The pallet is advanced atstation B into the fingers 18 of the fork carrier and is retainedtherein by the detents 22. The third fork carrier 19 is located atstation C and has a pallet 14 supported therein. Upon the next rotationof the hub 48 clockwise as illustrated in FIG. 1, the pallet at thestation C will be advanced to station A and the empty fork carrier atthe station A will be advanced to the station B. The fork carrier atstation B with the pallet from the conveyor 97 therein will advance tothe station C. The fork carrier advanced to station B will be alignedwith the conveyor 97 in position to receive the pallet 14 at the endthereof. Upon the return movement of the rod 30 to the left, as viewedin FIG. 7, and upon its 90 rotation, the pins 31 will be positioned oneither side of the pallet which will be advanced onto the ways 21 whenthe rod 31 is again advanced toward the finishing end of the machine.The pallet 14 at the station A, rests up spaced rails 154 mounted on atop plate 155 of a bracket 156. When the pallet 14 is advanced from thefork carrier, guide elements 157 having sloping side and bottom surfaces160 engage the forward corners of the pallet and accurately guide itonto the rails 21.

The transfer device 37 at the opposite or finishing end. of the machinewill have the fork carrier at station A disposed in alignment with theways 21 to receive the pa]- let [4 having the finished workpiecethereon. The pallet will be advanced onto the finger 18 by the pins 31on the rod when the rod is advanced toward the finishing end of themachine. The fork carrier at the station B will hold a pallet 14 foradvancement to station C while the fork carrier at the station C hasdelivered its pallet to the conveyor 97. Upon the counterclockwiserotation of the hub 48 as viewed in FIG. 1, the fork carrier at stationB will deposit its pallet onto the conveyor 97 while the pallet on thefork carrier at the station A will be advanced 120 to the station C. Thefork carrier at the station C will move upwardly to the station A withits fingers 18 aligned with ways 21 at the finishing end of the machinefor receiving the endmost pallet when the rod 30 advances it therefrom.

Automatic means may be provided for removing and in serting a newworkpiece in the fixture 15 of either trans fer device. The finishedworkpiece may be removed and a new workpiece to be machined may beinserted in the fixture manually. Such a change of workpieces may be Iperformed in the transfer device 36 at the station 13 before the palletis advanced to station A or in the device 37 at the station B before thepallet is advanced to station C.

The shaft 88 of the gear 43 is connected to a shaft 89 of a motor 92 bya key 91. The motor 92 is preferably of the fluid type, driving theshaft 89 at an accelerated speed until near the end of the 120advancement of the hub 48 when the speed is reduced and the hub 48substantially stopped.

A stop pin 98 is carried by the housing 42 within a bushing 99 toaccurately position the hub 48 in each of the 120 positions ofadvancement. A tapered end 101 of the pin 98 enter the tapered end ofone of three bushings 102 secured to the hub 48 by a plurality of screws103. A piston within a cylinder 104 operates a piston rod 105 which isreleasably connected by the head of a screw 106 to the stop pin 98. Theopposite end of the rod 105 carries a pair of washers 107 and 108 whichoperate switches 109 and 111. In the advance position of the stop pin98, the washer 107 actuatcs the switch 109 while the washer 108 hasmoved out of engagement with the operating finger of the switch 111.

After the stop pin 98 has been withdrawn, the motor 92 is energized fordriving the hub 48 toward the next 120 stop position. The fiuid motoraccelerates to drive the gears and hub to advance the fork carrierstoward the next 120 positions. As the hub approaches the 120 positions,the motor is rapidly dcceleratcd and stopped when the stop pin 98 isadvanced to engage a bushing 102 to therefore accurately locate the huband the fork carriers at the end of each 120 advancement. The hub isprovided with a ring 112 having three sloping cam surfaces 113 capableof engaging a ball 114 of a plunger 115 which engages a wheel 116 on aplunger 117 of a valve 118. As the ball rides up the cam surface 113, itdepresses the plunger 117 thereby progressively cutting off the flow offluid to the fluid motor 92 and thereby rapidly decelerating the motorand the driving of the hub 48 to the next 120 stop position. The ring112 is supported by bolts 119 extending through slots 121 in the hubwhich permits the ring to be accurately adjusted to locate the stoppositions. When the switch 109 is energized upon the advancement of thepin 98, a circuit is completed which permits the transfer bar 30 to beoperated in the ill normal sequence of operation of the machine. Thisoperation can only occur when the stop pin 98 is in forward position andwhen in such position the hub 48 and the fork carriers cannot beadvanced. When the stop pin is retracted, the switch 111 completes acircuit which permits a valve to be energized in the normal operation ofthe machine cycle for delivering fluid to the motor 92 in a circuitshunted about the circuit of the valve 118 which remains depressed untilthe hub advances to have the cam surface 113 pass over the ball 114 topermit the plunger 117 to retract. A dog 122 is carried on the end ofeach of the arms 55 in position to strike an arm 123 of a switch 124 forthe purpose of operating a valve for admitting fiuid to the cylinder 104to advance the stop pin 98 at each 120 advancement of the hub 48.

A switch actuating arm 125 extends from a quadrant 126 which is mountedon a pivot 127. The quadrant and arm are urged upwardly by a spring 128,the former being stabilized between the ends of pins 129 carried by arms131. A block 132 extends at right angles to the end. of the arm 125 andis provided with a slot to receive a roller 133 pivoted on a pin 134. Asillustrated in FIGS. 3 and 7, when a pallet is disposed in the device 36located at station A, it engages the roller 133 and deflects the arm 125downwardly to have an extending block 135 operate an arm 136 of a switch137. The block has an adjusting screw 138 which is set to assure theoperation of the switch when the roller 133 on the arm 125 is deficctedby a pallet. The switch 137 prevents the transfer device 36 from beingoperated when the pallet is located at station A. When the pallet isremoved, the spring 128 draws the arm 125 upwardly and the arm 136 ofthe switch 137 is moved to its initial position. When the arm 125 isdepressed, the switch 136 also sets up a circuit which permits the bar30 to be drawn towards the finishing end of the machine after the cycleof machine operations are completed. If no pallet is present the arm 125is not deflected and the bar 30 cannot be advanced.

The conveyor 97 is composed of two silent chains 139 which are drivenover a pair of sprockets 141 and 142 at the opposite ends of themachine. The chain runs ride in troughs 143 at the top and 144 at thebottom of the conveyor. The chains have central guides which engagecentral recesses in the teeth of the sprocket to maintain the chainsaligned thereon. The sprockets 142 are mounted on a shaft 145 carried byspaced plates 146. The plates are aligned with screws 147 by which theplates 146 and sprockets 142 are moved outwardly of the end of themachine to tighten the chains. Studs 148 on the frame of the conveyorextend through slots 149 in the plates 146 to secure the plates inadjusted position. The sprockets 141 are driven by a shaft 151 through aspeed reducer 152 from a motor 153. The chains are driven continuouslyand the speed may vary over a substantial range, a speed of 2 feet asecond has proven satisfactory.

A plunger 158, as illustrated in FIG. 4 is disposed in the path ofadvancement of the pallet 14 on the conveyor 97 at the starting end ofthe machine urged toward the endmost pallet by a spring 159. When theplunger 158 is deflected by a pallet sufficiently to assure the completeadvancement of the pallet in the fingers 18, a rod 161 on the plungerengages an arm 162 of a switch 163. If the arm 125 is no longerdellected, the switch 163 permits the operation of the valve to reversethe flow of fluid to the cylinder 104 to retract the stop pin 98. Whenthis occurs, switch 111 is energized to operate a valve which bypassesthe decelerating valve 118 and provides a flow of fiuid to the motor 92to drive the hub 48. As the pallets are advanced by the conveyor 97 tostation C' from which they are raised, the endmost pallet strikes alockout detent 170 which is aligned with the slot 17 formed by thespacer 16 with the pallet. The end 164 or 164' will be struck by thespacer 16 and the shock of the striking force is taken by a spring 165on the slide block 166 sup porting the detent. The detent 170 is securedto the block by a pivot pin 167 with the end 164' having an extendingfinger 168 containing a downwardly facing slot 169. A pin 171 carried byan L-shaped bracket 172 is supported on a boss 173 and guided on a pin174 in a sleevelined aperture 175 in the boss. The downwardly extendingportion of the bracket 172 is connected to a piston rod 176 of a pistonwithin a cylinder 177. When a pallet is to be advanced, the piston rod176 is moved to the left as viewed in FIG. 8, rocking the detent 170clockwise, thereby releasing the forward end of the spacer 16 and thepallet 14 while having the end 164 engage the spacer of the nextsucceeding pallet and thereby retaining it from advancing. When thepiston rod 176 is moved to the right, the arm 178 of a switch 179 isreleased by a washer 181 on the remote end of the piston rod from thatengaging the bracket 172. The washer 181 strikes an arm 182 of a switch183 to operate the contacts thereof.

A pivoted shaft 184 carries an arm 185 which is urged upwardly into thepath of the pallet by a spring 186. The arm carries a stop finger 187having an adjusting screw 188 thereon for limiting the upward movementof the arm 185. The shaft has an arm 189 fixed thereto supporting anadjusting screw 191 which engages the arm of a switch 192. As the palletis advanced, the forward edge engages the arm 185 and causes it todeflect to thereby operate the switch 192 near the end of itsadvancement. When passing beyond the arm 185, the spring 186 urges thearm upwardly and prevents the pallet from rebounding from the fingers ofthe fork carrier. The closing of the contacts of the switch 192 removesanother lockout which prevented the transfer device 36 to operate untilthe pallet is locked within the carrier.

The conveyor 97 is supported on uprights 200 having cross members 201carrying longitudinally extending rails 202 which support the upperchannel members 143. Cross members 203 are secured to the lower part ofthe uprights and support an upwardly presenting channel member 204 onwhich the channel members 144 are secured. Uprights 205 having crossmembers 206 at the top are joined by an upper longitudinally extendingelement 207 and bottom elements 208. Rectangular frames 209 enclose thetransfer devices 36 and 37. The frames 209 and the uprights 205 arecovered by expanded metal sheets 2-11 or sheets of other type of screenmaterial. The conveyor 97 and the transfer devices 36 and 37 areenclosed by the screen material and are protected from having articlesand large particles fall thereinto.

After machine operations have been employed on the workpieces clamped inthe fixtures .15 at all of the stations, and when the pallets carried bythe fork carriers are properly located at station A, B, C, A and B, therod 30 is moved to the right, toward the finishing end of the machine.The movement of the rod to the right will advance all of the palletsalong the ways 21 and from the fingers 18 of the fork carrier at stationA onto the ways adjacent thereto and from the finishing end of themachine into the fingers 18 of the fork carrier at station A. Thetransfer mechanism 36 will then be advanced 120 clockwise to move thepallet from station B to station A before or after the rod 30 has beenmoved to the left. At the same time, or subsequent thereto, the transferdevice 37 can be advanced 120 counterclockwise moving the fork carrierat station B to station C and moving the fork carrier at the station Cto the station A in position to receive the endmost pallet at thefinishing end of the machine. The pallet at station B will be moved tothe station C onto the conveyor 97 which will advance the pallets fromthe fingers 18 of the fork carrier. The pallet at the forward end of theconveyor 97 will be moved into the fingers 18 of the fork carrier atstation C of the transverse device 36 and if the pallets are properlylocated in the carriers at stations A, C and A, the rod 30 with the pins31 disposed vertical can advance toward the finishing end of the machinewhen all of the interlocking servo mechanisms have unlocked the controlsystem. Valves,

pistons and cylinders are employed with the transfer devices 36 and 37and the conveyor 97 interlocked with each other and the devices of themachine to prevent the operation of the machine and the transversedevices at all times when the pallets are not accurately located in thefingers 18 of the fork carriers and when not accurately located at thevarious stations. The operating mechanism for the rod 30 is locked outand prevented from operating when the transfer devices are beingoperated or are in condition to be operated. If the transfer devices arenot properly located or the pallets are not in proper position either onthe conveyor or in the fingers of the fork carriers, the machine anddevices will not operate. This interlock also embodies the control forthe stop pin 98 which must be in position to locate the hub before therod 30 can be advanced with the transverse devices locked out ofoperation .until the stop pin 98 has been retracted.

As has been pointed out hereinabove, the fixture 15 has not beendescribed in detail since the fixtures will take many forms dependingupon the type of workpiece and the places thereon at which operationsmust be performed. The one herein illustrated is merely shown by way ofexample.

What is claimed is:

1. In a rotary transfer device, a hub rotatably mounted on a fixed stubshaft, arms extending from said hub spaced equal angular distance apart,fork carriers having stub shafts pivotally mounted on the ends of thearms, crank arms fixed to said stub shafts, means interconnecting saidcrank arms for retaining the fork carriers in horizontal position at alltimes, a fluid motor for driving said hub, a decelerating valveconnected to said motor, and cam means canried by said hub for operatingsaid valve for decelerating said hub at the end of each angularadvancement.

2. In a rotary transfer device, a hub rotatably mounted on a fixed stubshaft, arms extending from said hub spaced equal angular distance apart,fork carriers having stub shafts pivotally mounted on the ends of thearms, crank arms fixed to said stub shafts, means interconnecting saidcrank arms for retaining the fork carriers in horizontal position at alltimes, a fluid motor for driving said hub, a decelerating valveconnected to said motor, cam means carried by said hub for operatingsaid valve for decelerating said hub at the end of each angularadvancement, and means for accurately positioning said hub at the end ofeach advancement.

3. In a rotary transfer device, a hub rotatably mounted on a fixed stubshaft, arms extending from said hub spaced equal angular distance apart,fork carriers having stub shafts pivotally mounted on the ends of thearms, crank arms fixed to said stub shafts, means interconnecting saidcrank arms for retaining the fork carriers in horizontal position at alltimes, a fluid motor for driving said hub, a decelerating valveconnected to said motor, cam means carried by said hub for operatingsaid valve for decelerating said hub at the end of each angularadvancement, and means for accurately positioning said hub at the end ofeach advancement, said positioning means embodying a fluid actuated pinwhich engages one of a plurality of apertures in the hub, and meansactuated by one of the hub arms near the end of its advancement forproducing the advancement of said pin.

4. In a rotary transfer device, a hub rotatably mounted on a fixed stubshaft, arms extending from said hub spaced equal angular distance apart,fork carriers having stub shafts pivotally mounted on the ends of thearms, crank arms fixed to said stub shafts, means interconnecting saidcrank arms for retaining the fork carriers in horizontal position at alltimes, a fluid motor for driving said hub, a decelerating valveconnected to said motor, cam means carried by said hub for operatingsaid valve for decelerating said hub at the end of each angularadvancement, means for accurately positioning said hub at the end ofeach advancement, said positioning means embodying a fluid actuated pinwhich engages one of a plurality of apertures in the hub, means actuatedby one of the hub arms near the end of its advancement for producing theadvancement of said pin, a spring pressed arm in the path of movement ofa pallet to be delivered to the fork of the carrier, said arm beingdeflected by said pallet, and a mechanism operated when said arm isdeflected for preventing the transfer device from opera-ting until saidarm is released and the pallet is retained in the fork by said arm.

5. In a rotary transfer device, a hub rotatable about a fixed stubshaft, means for driving said hub in rotation in 120 angular steps, armsextending from said hub located 120 apart, stub shafts in the ends ofthe arms pivotally supporting pallet carriers, crank arm fixed to saidstub shafts, a Y-shaped element having arms 120 apart with the center ofthe element pivoted to the crank arm on the hub stub shaft and the armsof the element pivoted to the crank arms on the stub shaft of thecarriers, said crank arms remaining parallel at all times to therebyretain the pallet carriers in horizontal planes in all positions, cammeans within said hub located 120 apart, and a decelerating valveactuated by one of said cam means near the end of the 120 advancement ofthe hub for progressively reducing the supply of fluid to the motor todecelerate the hub until its it stopped.

6. In a rotary transfer device, a hub rotatable about a fixed stubshaft, means for driving said hub in rotation in 120 angular steps, armsextending from said hub apart, a decelerating valve actuated by one ofsaid cam means near the end of the 120 advancement of the hub forprogressively reducing the supply of fluid to the motor to deceleratethe hub until it is stopped, a stop pin, and means actuated by one ofthe hub arms near the end of its 120 travel for energizing mean-s foradvancing the pin into an aperture in the hub to accurately locate it inadvanced position.

7. In a rotary transfer device, a hub rotatable about a fixed stu-bshaft, means for driving said hub in rotation in 120 angular steps,arm's extending from said hub located 120 apart, stub shafts in the endsof the arm-s pivotally supporting pallet carriers, crank arm fixed tosaid stub shafts, a Y-shaped element having arms 120 apart with thecenter of the element pivoted to the crank arm on the hub stub shaft andthe arms of the element pivoted to the crank arms on the stub shaft ofthe carriers, said crank arms remaining parallel at all times to therebyretain the pallet carriers in horizontal planes in all positions, cammeans within said hub located 120 apart, a decelerating valve actuatedby one of said cam means near the end of the 120 advancement of the hubfor progressively reducing the supply of fluid to the motor todecelerate the hub until it is stopped, a stop pin, means actuated byone of the hub arms near the end of its 120 travel for energizing meansfor advancing the pin into an aperture in the hub to accurately locateit in advanced position, and means actuated upon the advancement of saidpin into said aperture to prevent the rotation of the hub while engagedby said pin.

References Cited by the Examiner UNITED STATES PATENTS 1,837,605 12/1931Baker 198-85 2,161,750 6/1939 Schonwald 198211 2,201,231 5/1940 Haupt198-21l X 2,670,860 3/1954 Cogings 198-211 X 2,791,317 5/1957 Cohrs198--209 X 2,792,105 5/ 1957 Wilson 198-211 3,005,535 10/ 1961 Kerns 198-49 X 3,023,880 3/ 1962 Gartner 19885 3,133,622 5/1964 Immesberger198-49 SAMUEL F. COLEMAN, Primary Examiner.

EDWARD A. SROKA, Examiner.

1. IN A ROTARY TRANSFER DEVICE, A HUB ROTATABLY MOUNTED ON A FIXED STUBSHAFT, ARMS EXTENDING FROM SAID HUB SPACED EQUAL ANGULAR DISTANCE APART,FORK CARRIERS HAVING STUB SHAFTS PIVOTALLY MOUNTED ON THE ENDS OF THEARMS, CRANK ARMS FIXED TO SAID STUB SHAFTS, MEANS INTERCONNECTING SAIDCRANK ARMS FOR RETAINING THE FORK CARRIERS IN HORIZONTAL POSITION AT ALLTIMES, A FLUID MOTOR FOR DRIVING SAID HUB, A DECELERATING VALVECONNECTED TO SAID MOTOR, AND CAM MEANS CARRIED BY SAID HUB FOR OPERATINGSAID VALVE FOR DECELERATING SAID HUB AT THE END OF EACH ANGULARADVANCEMENT.